What unit categories does the tool support?

The tool covers five categories: length, weight, temperature, speed and volume, with 30 units in total. For digital storage sizes, use the byte converter.

Is my data sent to a server?

All conversions are pure JavaScript calculations in your browser. Our servers are not involved at any point.

How precise are the conversions?

Conversion factors use the exact definitions: 1 in = 2.54 cm, 1 lb = 0.45359237 kg and 1 US gallon = 3.785411784 L, with the other units derived from these. Results are shown to up to 6 significant figures, in exponential notation for values of 1,000,000 or more or below 0.0001.

Can I convert temperatures?

Yes. Celsius, Fahrenheit and Kelvin use offset formulas rather than a single factor: °F = °C × 9/5 + 32 and K = °C + 273.15. A value below absolute zero (−273.15 °C, −459.67 °F or 0 K) is flagged instead of converted.

Unit converter

Unit converter is a calculator tool that converts measurements across 30 units in five categories: length, weight, temperature, speed and volume. Enter a value, pick its unit, and every other unit in the category is shown at once, using the exact conversion factor definitions. The tool runs in your browser.

Millimeter (mm)10

Meter (m)0.01

Kilometer (km)1.0000e-5

Inch (in)0.393701

Foot (ft)0.0328084

Yard (yd)0.0109361

Mile (mi)6.2137e-6

Converting from: Centimeter (cm)

Conversion categories

Direct links for each unit type.

Length converter

Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles. Instant results. Runs in your browser.

Weight converter

Convert between milligrams, grams, kilograms, ounces, pounds, and stone as you type, using the exact 0.45359237 kg pound. Runs in your browser.

Temperature converter

Convert between Celsius, Fahrenheit, and Kelvin as you type. Uses the exact offset formulas and flags values below absolute zero. Runs in your browser.

Speed converter

Convert between meters per second, kilometers per hour, miles per hour, and knots. Instant results. Runs in your browser.

Volume converter

Convert between milliliters, liters, teaspoons, tablespoons, cups, fluid ounces, pints, quarts, and gallons. Runs in your browser.

How to convert units

Select the measurement category: length, weight, temperature, speed or volume.
Enter the value you want to convert in the input field.
Choose the unit of your value from the dropdown. Every other unit in the category is listed below.
The converted value appears instantly, click to copy it.

Common uses

Converting metric measurements to imperial (or vice versa) for international documents or recipes
Checking unit conversions for engineering or scientific work. When you then need the size of a change between two readings, work out the percentage change.
Converting temperatures between Celsius, Fahrenheit, and Kelvin. For storage sizes, convert between KB, MB, and GB instead.

Technical specification

Algorithm or formula: Linear multiplication against a per-category SI conversion factor (e.g., 1 lb = 0.45359237 kg, 1 mi = 1609.344 m, 1 US gallon = 3.785411784 L). Temperature uses offset formulas (°F = °C * 9/5 + 32, K = °C + 273.15) rather than ratios.
Browser API or library: Pure JavaScript arithmetic; no external library.
Input limits: Any IEEE 754 double-precision value. 5 categories, 30 units. Temperatures below absolute zero are rejected.
Output: Each converted value is shown to up to 6 significant figures (exponential notation at or above 1,000,000 or below 0.0001), with a Copy button per result.
Known limitations: Currency conversion is not included (rates change in real time). Temperature differences (delta) and absolute temperatures both use absolute conversion; for delta-only conversions, multiply directly by the ratio.

Frequently asked questions

What unit categories does the tool support?: The tool covers five categories: length, weight, temperature, speed and volume, with 30 units in total. For digital storage sizes, use the byte converter.
Is my data sent to a server?: All conversions are pure JavaScript calculations in your browser. Our servers are not involved at any point.
How precise are the conversions?: Conversion factors use the exact definitions: 1 in = 2.54 cm, 1 lb = 0.45359237 kg and 1 US gallon = 3.785411784 L, with the other units derived from these. Results are shown to up to 6 significant figures, in exponential notation for values of 1,000,000 or more or below 0.0001.
Can I convert temperatures?: Yes. Celsius, Fahrenheit and Kelvin use offset formulas rather than a single factor: °F = °C × 9/5 + 32 and K = °C + 273.15. A value below absolute zero (−273.15 °C, −459.67 °F or 0 K) is flagged instead of converted.

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Reviewed and tested September 30, 2026.